Recently, semiconductor processes have become further finer. Fine patterns are measured and inspected using a microscope. Images of processed patterns are taken by the microscope and displayed on a display, and inspection and measurement (which hereinafter may be simply referred to as “inspection”) are performed using an image processing technique.
In the case of inspecting processed circuit patterns in the middle of semiconductor processes, inspection of all the patterns on a semiconductor chip is ineffective. Accordingly, areas where a malfunction tends to occur in the process or occurred in the past are specified, and inspection is performed.
At this time, it is significantly difficult to find the specified areas to be subjected to the inspection using a microscope having a high resolution. A method that is referred to as template matching disclosed in Patent Literature 1 is used.
The template matching is a method of specifying a desired target pattern in a search region on a sample. On each position in the search region, a degree of matching with a pattern image, which is referred to as a template, is determined, and a position indicating the highest degree of matching with the template in the search region is identified, thereby specifying the position. The operation is performed by a computer. More specifically, a plurality of gradation values representing the unevenness of a pattern in the microscope image are compared with a template diagram in a certain region. If the degree of matching is high, it is determined that matching is achieved. Preliminary registration of position information and the template allows automatic measurement.